1. Field of the Invention
The present invention relates to a liquid discharge head and a manufacturing method of the liquid discharge head that performs recording on a recording medium by discharging the liquid from a discharge port.
2. Description of the Related Art
A liquid discharge head is known, wherein the liquid discharge head includes a liquid discharge energy generating element that generates energy for discharging liquid droplets, and a discharge port member having a discharge port on a substrate. A flow path is formed between the liquid discharge energy generating element and the discharge port member. When liquid reserved in the flow path is discharged from the discharge port, liquid droplets land on a recording medium such as a recording paper to form dots, whereby the recording is performed.
In recent years, a liquid discharge head has been suggested wherein the liquid discharge head includes a plurality of discharge ports having different opening areas. The liquid discharge head may discharge the liquid droplets having different sizes from one liquid discharge head, whereby a place having a fine dot is recorded with a small-sized liquid droplet and a place having a large dot is recorded with a large-sized liquid droplet so that the printing time can be shortened without decreasing the recording quality.
If a discharging characteristic such as a discharging speed or refill time (the time between after the liquid droplet is discharged to fill a flow path with the liquid that is supplied within the flow path) is different for each of the discharge ports in the liquid discharge head in which the liquid droplets having different sizes are discharged, there is a concern that the recording quality may be deteriorated.
Thus, US Patent Publication No. 2008/024574 discloses a liquid discharge head in which the thicknesses of the discharge port member are different depending on the size of the opening area of the discharge port.
The method includes: providing a first layer, which becomes a first portion of the discharge port member, on a flow path wall member of the substrate on which the flow path wall member is provided, forming a first discharge port in the first layer, and providing a second layer, which becomes a second portion of the discharge port member, on the first layer. Then the second discharge port is formed in the second layer. However, bonding strength between the first portion and the second portion of the discharge port member that is partially provided on the first portion of the discharge port member is not sufficient according to the materials of the first layer and the second layer, and there are cases where the reliability of the discharge port member is affected in the long term.